Tweak max health syncing calculation, add config option

bukkit/src/main/java/net/william278/husksync/data/BukkitData.java

@@ -810,8 +810,7 @@ public abstract class BukkitData implements Data {
         public static BukkitData.Health adapt(@NotNull Player player) {
             return from(
                     player.getHealth(),
-                    Objects.requireNonNull(player.getAttribute(Attribute.GENERIC_MAX_HEALTH),
-                            "Missing max health attribute").getValue(),
+                    getMaxHealth(player),
                     player.getHealthScale()
             );
         }
@@ -822,9 +821,10 @@ public abstract class BukkitData implements Data {
 
             // Set base max health
             final AttributeInstance maxHealthAttribute = Objects.requireNonNull(
-                    player.getAttribute(Attribute.GENERIC_MAX_HEALTH), "Missing max health attribute");
+                    player.getAttribute(Attribute.GENERIC_MAX_HEALTH), "Max health attribute was null"
+            );
             double currentMaxHealth = maxHealthAttribute.getBaseValue();
-            if (maxHealth != 0d) {
+            if (plugin.getSettings().doSynchronizeMaxHealth() && maxHealth != 0d) {
                 maxHealthAttribute.setBaseValue(maxHealth);
                 currentMaxHealth = maxHealth;
             }
@@ -853,6 +853,30 @@ public abstract class BukkitData implements Data {
             }
         }
 
+        /**
+         * Returns a {@link Player}'s maximum health, minus any health boost effects
+         *
+         * @param player The {@link Player} to get the maximum health of
+         * @return The {@link Player}'s max health
+         */
+        private static double getMaxHealth(@NotNull Player player) {
+            double maxHealth = Objects.requireNonNull(
+                    player.getAttribute(Attribute.GENERIC_MAX_HEALTH), "Max health attribute was null"
+            ).getBaseValue();
+
+            // If the player has additional health bonuses from synchronized potion effects,
+            // subtract these from this number as they are synchronized separately
+            if (player.hasPotionEffect(PotionEffectType.HEALTH_BOOST) && maxHealth > 20d) {
+                final PotionEffect healthBoost = Objects.requireNonNull(
+                        player.getPotionEffect(PotionEffectType.HEALTH_BOOST), "Health boost effect was null"
+                );
+                final double boostEffect = 4 * (healthBoost.getAmplifier() + 1);
+                maxHealth -= boostEffect;
+            }
+
+            return maxHealth;
+        }
+
         @Override
         public double getHealth() {
             return health;

common/src/main/java/net/william278/husksync/config/Settings.java

@@ -177,7 +177,11 @@ public class Settings {
 
     @YamlComment("(Experimental) Persist Cartography Table locked maps to let them be viewed on any server")
     @YamlKey("synchronization.persist_locked_maps")
-    private boolean persistLockedMaps = false;
+    private boolean persistLockedMaps = true;
+
+    @YamlComment("Whether to synchronize player max health (requires health syncing to be enabled)")
+    @YamlKey("synchronization.synchronize_max_health")
+    private boolean synchronizeMaxHealth = true;
 
     @YamlComment("Whether dead players who log out and log in to a different server should have their items saved. "
             + "You may need to modify this if you're using the keepInventory gamerule.")
@@ -352,6 +356,10 @@ public class Settings {
         return synchronizeDeadPlayersChangingServer;
     }
 
+    public boolean doSynchronizeMaxHealth() {
+        return synchronizeMaxHealth;
+    }
+
     public int getNetworkLatencyMilliseconds() {
         return networkLatencyMilliseconds;
     }

docs/Config-File.md

@@ -77,7 +77,9 @@ synchronization:
   # Where to display sync notifications (ACTION_BAR, CHAT, TOAST or NONE)
   notification_display_slot: ACTION_BAR
   # (Experimental) Persist Cartography Table locked maps to let them be viewed on any server
-  persist_locked_maps: false
+  persist_locked_maps: true
+  # Whether to synchronize player max health (requires health syncing to be enabled)
+  synchronize_max_health: true
   # Whether dead players who log out and log in to a different server should have their items saved. You may need to modify this if you're using the keepInventory gamerule.
   synchronize_dead_players_changing_server: true
   # How long, in milliseconds, this server should wait for a response from the redis server before pulling data from the database instead (i.e., if the user did not change servers).